The present invention relates to a tube fitting having an air inlet at one end and an air outlet at other end adapted for use in connecting an air tool to the air outlet and a tube or pipe to the air inlet for supplying pressurized air to the air tool. More particularly, the present invention relates to a tube fitting for effectively absorbing a vibration and shock transmitted to the pipe fitting during use.
In various manual air tools actuated by pressurized air, a tube fitting is used at an air inlet or outlet portion of the air tool, or an intermediate portion of the pressurized air path. The tube fitting is connected to an air source by means of a pressure-resistant and flexible hose or tube to be inserted into the connection end of the tube fitting for permitting the predetermined pressurized air to flow therethrough. In addition, the tube fitting is required to tighten and hold the tube to be connected at the inserted position to maintain the firm connection. There is also known a tube fitting which is able to disconnect from the tube by releasing a coupling, while keeping the connection between the tube fitting and the air tool. As an example of this type of tube fitting, there have been conventionally proposed and used a plug-in quick tube coupler which enables to connect and disconnect the tube fitting to and from the pressurized fluid supply line. The quick tube coupler is disclosed in Japanese Patent Application Laid-Open Publication Nos. 8-277985, 9-68293, 9-96384, or 9-184588.
The quick tube coupler is used for relatively high pressurized air to actuate the air tool. Accordingly, it is necessary for the tube constituting a flow path for the pressurized air and the tube fitting arranged at various positions of the fluid flow path to provide appropriate pressure resistance in consideration for safety. The connecting tube tends to increase inflexibility during use due to the pressure resistant structure of the tube and a pressure applied from the pressurized air flowing therethrough. Since a manual pneumatic device, such as a manual air tool, is used to be carried to positions by hand where it is used, the connecting tube is required to have such flexibility so as to be able to quickly and reliably follow the hand carrying action of the air tool.
When the tube fitting is supplied with pressurized air, the air supplying side of the tube fitting is subjected to continuously transmitted vibration and shock due to pressurization from the air compression source. In addition, the transmitted vibration and shock propagate to the hand operated air tool via the connecting tube. On the other hand, counter vibrations and shocks due to air pressure discharged from the air tool during the operation or air exhaust from the air tool are transmitted to the air compression source via the tube fitting and the connecting tube. Thus, there has been a possibility of causing various unfavorable effects not only to the tube fitting, but also to the air compression source, the hand operated air tool, and workers.
It is possible to solve effects based on vibration and shock during the use of the tube fitting by providing a vibration absorbing mechanism or vibration buffering mechanism in the flow path of the pressurized air. If such a vibration absorbing mechanism or vibration buffering mechanism is independently provided in the flow path, the flow path system itself becomes unnecessarily complicated or complex. Further, various unfavorable problems arise such as degrading the workability, causing a failure, and the like. This is not always effective countermeasure.